1. Field of the Invention
The present invention relates to a spin injection electrode structure, a spin transport element, and a spin transport device.
2. Related Background Art
Techniques for accumulating spins in channels made of semiconductors have recently been known. The channels made of semiconductors have spin diffusion lengths much longer than those of channels made of metals. For example, the following Non Patent Literatures 1 to 4 disclose techniques for injecting spins into silicon.    Non Patent Literature 1: Tomoyuki Sasaki et al., “Electrical Spin Injection into Silicon Using MgO Tunnel Barrier,” Applied Physics Express 2, The Japan Society of Applied Physics, 2009, p. 053003-1 to 053003-3.    Non Patent Literature 2: O. M. J. van't Erve et al., “Electrical injection and detection of spin-polarized carriers in silicon in a lateral transport geometry,” APPLIED PHYSICS LETTERS 91, American Institute of Physics, 2007, p. 212109-1 to 212109-3.    Non Patent Literature 3: Y. Ando et al., “Electrical injection and detection of spin-polarized electrons in silicon through an Fe3Si/Si Schottky tunnel barrier,” APPLIED PHYSICS LETTERS 94, American Institute of Physics, 2009, p. 182105-1 to 182105-3.    Non Patent Literature 4: Saroj P. Dash et al., “Electrical creation of spin polarization in silicon at room temperature,” nature, Macmillan Publishers Limited, Nov. 26, 2009, vol. 462, p. 491-494.